1. Field of the Invention
The present invention relates to a wafer support device capable of being incorporated into devices for transferring semiconductor wafers (which will be hereinafter referred to as wafers) to and from wafer boats or the like.
2. Description of the Related Art
In the course of manufacturing semiconductor integrated circuits, particularly in the processes of diffusing, oxidizing and CVD-treating wafers, it is preferable that these processes be conducted under clean circumstances with clean equipment and without using human hands since they tend to be sources for generating dust. When these processes are conducted in this manner, circuit elements of high density and quality can be produced. Various kinds of wafer carrying devices are used to this end. When wafers are to be heated, they are picked up directly from a carrier and transferred to a wafer boat made of quartz. They are then carried to a heat treatment furnace. There is also a case where they are once moved from the carrier to a buffer and then transferred from the buffer to the boat. They are further carried to the predetermined processing apparatus by the boat and subjected to the various manufacturing processes there. The manufacturing and processing apparatuses include those of the batch type and of the continuation type and they are grouped into the ones for processing wafers vertically supported and the ones for processing wafers horizontally supported.
In the case of the manufacturing and processing apparatus of the batch type, the transfer of wafers is attained by such a device as shown in FIG. 1. Numeral 1 represents a support member having a curved top. Support member 1 supports plural wafers (W), which are housed in carrier 4, from below in groove 2 formed on the curved top thereof. When it is driven by driver means 3, support member 1 lifts plural wafers (W) or 25 pieces of wafers (W) above carrier 4 at the same time. Wafers (W) kept under this state are held between holder member 5, which transfers wafers (W) from carrier 4 to a boat (not shown). After being processed, wafers (W) are transferred from the boat to the carrier. When any of the wafers (W) are broken during the transferring, however, broken pieces of the wafer adhere to support member 1. When multistage furnaces are used and the manufacturing process conducted in each of the reaction furnaces is different from the others, components of wafers (W) processed in the previous reaction furnace become impurities, which also adhere to support member 1 and holder member 5. This makes it necessary to use new support and holder members for every manufacturing and processing apparatus or to prepare plural support and holder members for both of wafers (W) not processed yet and those processed. Further, the support and holder members must be washed and cleaned every time when the processing of wafers (W) is finished. The washing and cleaning of the support and holder members are so troublesome as to reduce the productivity of the manufacturing and processing apparatuses.